Background: Solitary cystic lesion of the neck may often be the only initial presenting symptom for branchial cleft cysts and cystic metastases.
Aims/objectives: To analyse the malignancy rate detected in patients undergoing surgical treatment for lateral branchial cleft cyst.
Material and methods: The records of all patients with surgical procedure code ENB40 (Excision of lateral branchial cleft cyst- or fistula) between 2003 and 2019 were reviewed. After excluding 150 patients, 436 patients were included for final analysis. Re-evaluation of the cytology including HPV-analysis was performed in those who had a malignant cyst.
Results: Cystic metastases were demonstrated histologically after surgical excision in 13 patients (3%). In patients over 18 years of age, the prevalence of cystic metastasis regardless of the primary tumour type was 3.3%.
Conclusion and significance: When the investigation protocol for solitary cystic lesions of the neck is followed, the negative predictive value for malignancy is 97%. All adult patients with a cytologic verified diagnosis of branchial cyst should be examined with HPV-analysis of the cystic sample before excision of the cyst. Failure of predicting a malignancy is often associated with cytology of poor cellularity which may be improved by more frequent use of ultrasound guided fine-needle aspiration cytology (FNAC).
Keywords: Branchial cleft cyst; HNSCC; HPV; cystic metastasis; cytology.